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Commit a84cd29335f4ca38ca8405c1636ee3876bb292b5

Authored by Sam Lang
Committed by Sage Weil
1 parent 8b3e1a5698
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

ceph: Use pseudo-random numbers to choose mds 

We don't need to use up entropy to choose an mds,
so use prandom_u32() to get a pseudo-random number.

Also, we don't need to choose a random mds if only
one mds is available, so add special casing for the
common case.

Fixes http://tracker.ceph.com/issues/3579

Signed-off-by: Sam Lang <sam.lang@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

Showing 1 changed file with 5 additions and 3 deletions Side-by-side Diff

... ... @@ -20,8 +20,11 @@
20 20 {
21 21 int n = 0;
22 22 int i;
23   - char r;
24 23  
  24 + /* special case for one mds */
  25 + if (1 == m->m_max_mds && m->m_info[0].state > 0)
  26 + return 0;
  27 +
25 28 /* count */
26 29 for (i = 0; i < m->m_max_mds; i++)
27 30 if (m->m_info[i].state > 0)
... ... @@ -30,8 +33,7 @@
30 33 return -1;
31 34  
32 35 /* pick */
33   - get_random_bytes(&r, 1);
34   - n = r % n;
  36 + n = prandom_u32() % n;
35 37 i = 0;
36 38 for (i = 0; n > 0; i++, n--)
37 39 while (m->m_info[i].state <= 0)